Sources of Food
Foods are classified according to source, chemical composition, physical properties and function.
In classifying food as to its source we have three classifications: animal, plant and mineral. Meat, fowl, fish, shell-fish, eggs, milk and its products, animal fat and gelatin help to constitute the animal foods. Seeds, roots, leaves, cereals, vegetables, fruits, sugar and vegetable oils are plant foods. From the mineral there are: iron, potassium, phosphorus, iodin, sulphur. These are obtained from the animal and plant foods. Water is not classed as a food, but it enters into the diet as a very important constituent.